The present invention is directed to the art of moisture detection systems. More particularly, the present invention is directed to an automated moisture detection system for monitoring the moisture content in the exterior walls or outer sheathing of commercial or residential structures and will be described with particular attention thereto. It is to be appreciated, however, that the present invention has a wide range of applications and uses such as, for example, in monitoring the moisture content in other components of buildings and for monitoring moisture in a wide range of manufacturing or industrial processes.
The present invention finds particular application in connection with buildings covered with cladding systems such as, for example, brick, metal or vinyl siding products. Most cladding systems are typically not designed to drain water that may unintentionally penetrate past the exterior cladding due to defective window construction improper installation, the lack of proper flashing, or the like. Such deficiencies may lead to certain moisture induced damage to the materials beneath the cladding system.
As a further concern, weather resistive barriers are typically not provided beneath the cladding on commercial buildings and are often installed incorrectly on residential buildings. Furthermore, cavities on certain drainable cladding systems may become plugged or otherwise disabled, leading to accumulated moisture with no means of discharge from behind the cladding.
The damage to the building materials behind the exterior cladding is most often hidden and therefore usually undetectable by outer visual inspection. After prolonged periods of moisture ingress and/or moisture retention, damage occurs, usually in the form of mold, rot, and dimensional instability. There is no known automated, reliable technique for periodically testing for
There is a need, therefore, to provide a system for detecting moisture in building components on a substantially continuous basis so that elevated moisture levels in the building materials monitored may be immediately discovered and appropriately addressed quickly before any significant damage to the building materials can take place.
It would further be desirable to provide an automated moisture monitoring system that includes a central control unit connected to a plurality of moisture sensors, each of the moisture sensors being disposed in a different exterior wall portion of the monitored structure. In that way, each wall of the monitored structure can be interrogated on a regular and substantially continuous basis by the control unit for generating suitable alarms or the like when the moisture content in any of the monitored building walls exceeds a predetermined threshold.
Still further, it would be desirable to provide a monitoring system that generates audible or visual alarms when elevated moisture levels are detected in at least one exterior wall of the monitored structure. In addition, an electronic modem communication circuit would be advantageous in conjunction with the control unit for transmitting the moisture alarm signal to remote locations such as, for example, to a commercial service that provides notification to the building owner followed by a communication to appropriate service crews to effect necessary repairs, or the like.
The subject invention provides a method and apparatus for moisture detection in buildings with hard outer cladding that overcomes the above-noted problems through automated interrogation of moisture levels in the exterior walls of the structure and alarm signal generation when the detected moisture level in any of the monitored walls exceeds a predetermined threshold value.
In particular, and in accordance with one aspect of the invention, there is provided an apparatus for monitoring moisture content in sheathing of a building behind an exterior cladding system. The apparatus comprises a plurality of moisture sensors embedded respectively in a plurality of exterior walls of the building, and a control unit operatively connected with the a plurality of moisture sensors for generating an alarm signal when at least one of the moisture sensors detects a moisture level above a predetermined threshold value. Preferably, the plurality of moisture sensors installed in the building exterior walls each exhibit a resistance characteristic that varies in relation to the moisture content in the plurality of walls. In that way, the moisture sensors provide signals representative of the moisture content in the walls.
In accordance with a further aspect of the invention, the control unit includes an excitation signal circuit for generating an excitation signal applied to each of the plurality of moisture sensors. Each of the plurality of moisture sensors generates a signal representative of the moisture content in the respective wall in response to application of the excitation signal.
In yet a still further aspect of the invention, each of the moisture sensors includes a pair of spaced apart elongate conductive probe members embedded into the respective substrates of first and second walls of the structure, respectively. Further, each moisture sensor defines a connection end extending outwardly from the first and second walls, respectively, for enabling an electrical connection between the first and second moisture sensors and the control unit. The probe members are spaced apart about xc2xe inch. However, other suitable probe spacings can be used as well.
Preferably, for purposes of automation, the control unit is adapted to generate, at preselected time intervals, a periodic excitation signal for selective multiplexed application to each of the plurality of moisture sensors. The moisture sensors, in turn, generate a plurality of signals representative of the moisture content in each of the plurality of monitored walls. The moisture content signal is read across each pair of conductive probe members in turn.
In accordance with yet a further aspect of the invention, the control unit preferably includes a non-volatile memory or an electrically usable memory for storing monitor operating system code and a first memory for storing data values of each of the plurality of signals representative of the moisture content in each of the monitored walls from the plurality of moisture sensors. Further, outdoor temperature and relative humidity sensors are coupled to the control unit for sensing temperature and relative humidity of ambient air outside of the monitored building. The control unit includes, preferably, a second memory for storing, at each of the preselected time intervals, a second data value representative of the sensed temperature and relative humidity of the ambient air outside of the building. Alternatively, the moisture data values can be stored together with the temperature and relative humidity values in selected portions of a single shared memory device.
In accordance with yet a still further aspect of the invention, the control unit includes an alarm circuit for generating at least one of a visual alarm and an audible alarm when any of the signals representative of the moisture content in the plurality of monitored walls exceeds a predetermined threshold value. Preferably, the control unit further includes a communication circuit for communicating the alarm signal electronically to a location remote from the monitored building or structure.
In yet another aspect of the invention, a method is provided for detecting the presence of moisture behind cladding systems in exterior sheathing walls of a building. The method includes the steps of establishing a datum moisture parameter, periodically detecting a plurality of electrical moisture parameter values generated in a corresponding plurality of moisture sensors, and generating an alarm signal when at least one of the detected electrical parameter values is indicative of moisture in the exterior sheathing walls of the building in excess of the datum moisture parameter.
As can be seen from the foregoing, a primary object of the invention is the provision of a method and apparatus for automated monitoring of the moisture content in the plurality of exterior walls of a building covered by a hard exterior cladding.
A further object of the invention is the provision of an apparatus and method for detecting moisture in exterior sheathing walls of a building by disposing a plurality of moisture sensors in respective walls of the building, generating excitation signals from a control unit and thereby deriving moisture parameter values from each of the moisture sensors, and, when any of the detected moisture signals exceeds a predetermined moisture threshold parameter value, generating a visual and/or audible alarm signal representative of the sensed moisture intrusion.
Still other objects and advantages of the invention will become apparent to those skilled in the art upon a reading and understanding of the following detailed description.